linux-kernel - Aw: Re: Re: Re: [PATCH] Fix mt7622.dtsi thermal cpu

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Message-ID: <trinity-59bd4461-3429-4382-9754-90cf20287cad-1624624111998@3c-app-gmx-bs66>
Date:   Fri, 25 Jun 2021 14:28:32 +0200
From:   Frank Wunderlich <frank-w@...lic-files.de>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Eric Woudstra <ericwouds@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Sean Wang <sean.wang@...iatek.com>,
        Ryder Lee <ryder.lee@...iatek.com>,
        Daniel Golle <daniel@...rotopia.org>
Subject: Aw: Re:  Re: Re: [PATCH] Fix mt7622.dtsi thermal cpu

> Gesendet: Freitag, 25. Juni 2021 um 13:47 Uhr
> Von: "Daniel Lezcano" <daniel.lezcano@...aro.org>

> > but we need to disable the passive trip as cpu-trotteling starts there...the higher temperature trips are currently not reached
> 
> Sorry, can you rephrase it ? I'm not getting the point.

the problem currently is that passive is at 47degress Celsius and trottles cpu, active (67°C) and hot points are never reached this way. so at least we need to change temperatures in dtsi, and maybe disable cpu-trotteling on passive trip. imho fan will never start if it is in active and cpu is trottled before in passive

> > summary
> > 
> > moving fan and cpu_thermal-override to bananapi-r64.dts
> > 
> > passive-trip: cooling-device = <&cpu0/1 0 0> as in erics Patch
> > active trip: cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> > the other 2 unchanged
> > 
> > but i suggest changing the temperature points in mt7622 dtsi as this is SoC specific
> > 
> > so basicly:
> > 
> > --- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> > +++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> > @@ -143,13 +143,13 @@ cpu_thermal: cpu-thermal {
> > 
> >                         trips {
> >                                 cpu_passive: cpu-passive {
> > -                                       temperature = <47000>;
> > +                                       temperature = <70000>;
> 
> May be increase the passive temp to 75°C.
> 
> >                                         hysteresis = <2000>;
> >                                         type = "passive";
> >                                 };
> > 
> >                                 cpu_active: cpu-active {
> > -                                       temperature = <67000>;
> > +                                       temperature = <80000>;
> >                                         hysteresis = <2000>;
> >                                         type = "active";
> >                                 };
> 
> Move the active trip 'cpu_active' to mt7622-bananapi-bpi-r64.dts. and
> set it to 70°C in the mt7622-bananapi-bpi-r64.dts, so the fan will act
> before the cpu throttling.
> 
> The behavior should be the following: The temperature reaches 70°C, the
> fan will start, if the temperature continues to increase, it will
> increase the speed. If the temperature reaches 75°C, the fan is still
> rotating at full speed but the cpu begins to be throttled.

passive to 75 and active lower to 70? is this as intended that active comes before passive?

mt7622-bananapi-bpi-r64.dts:

&cpu_thermal {
	trips {
		cpu_passive: cpu-passive {
			temperature = <75000>;
			hysteresis = <2000>;
			type = "passive";
		};

		cpu_active: cpu-active {
			temperature = <70000>;
			hysteresis = <2000>;
			type = "active";
		};
	};

	cooling-maps {
		map1 {
			trip = <&cpu_active>;
			cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
		};
	};
};


> AFAIU, it is a Cortex-A53 running @1.35GH, so except the board is in a
> black metal box under the sun, I don't see how we can reach this thermal
> limits.
> 
> > @@ -170,8 +170,8 @@ cpu-crit {
> >                         cooling-maps {
> >                                 map0 {
> >                                         trip = <&cpu_passive>;
> > -                                       cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > -                                                        <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> > +                                       cooling-device = <&cpu0 0 0>,
> > +                                                        <&cpu1 0 0>;
> 
> You should keep it untouched.

then cpu is trottled at passive point (currently 47°C) and imho fan does not start at active

> >                                 };